New mosquito disease seen in Louisiana

U.S. Department of Agriculture via AP
An aedes aegypti mosquito is one of two types of believed to be responsible for spreading a painful joint infection called chikungunya.
An aedes aegypti mosquito is shown on human skin in this undated photo. THe insect is one of two types of mosquitoes believed responsible for spreading a painful joint infection called chikungunya.(Photo: U.S. Department of Agriculture v, U.S. Department of Agriculture v)

Mosquito season is upon us again, and LSU AgCenter entomologist Kristen Healy is warning people about a new risk this year.

“It has been about 12 years since West Nile virus, the mosquito-borne disease, was first identified in Louisiana, but this year the chikungunya fever has made its presence known,” Healy said.

She said the disease, which has been recognized in Asia and Africa for more than 60 years, was seen for the first time in the Western Hemisphere last December when it showed up in the Caribbean.

“We know of eight cases of chikungunya fever so far in the state of Louisiana,” Healy said. “There has been one case in Grant Parish, three cases in Jefferson, three in Orleans and one in Tangipahoa.”

Each of the cases was imported into the state, Healy said. “Three were from Haiti and five from the Dominican Republic.”

But because the disease is spread from person to person by mosquito bites, there is the possibility it will spread.

Healy assures people that doctors consider the disease to be relatively mild when compared with other mosquito-borne diseases like malaria, dengue fever and yellow fever.

“Some people will have been infected with the virus but show no symptoms, as with West Nile virus,” Healy said. “Those who have symptoms will normally experience joint pain and fever, which can last as long as six to eight months.”

The disease is transmitted by female Asian Tiger mosquitoes taking a “blood meal” – a requirement in the insect’s reproductive process – from an infected person and transmitting it to another person, Healy said.

This is different from West Nile virus transmission. That happens when mosquitoes bite infected birds, then bite humans.

She said the disease is unlikely - but possible - to be fatal. “This is especially true in the elderly, those who are seriously ill and newborns of infected mothers,” Healy said.

There is no treatment available for chikungunya.

“Really, all that we can do right now is provide some relief for the symptoms,” she said.

Because there is no treatment, she said the best defense people can take is simply making sure they are not providing a breeding ground for mosquitoes by leaving standing water around.

“This has been a good year for mosquitoes because of the large amount of rain in the state. That is part of the problem, but we have to take some of the blame also,” Healy said.

Mosquitoes can breed in any almost any amount of standing water. “You would be surprised at how the small amount of water held in a soft drink bottle cap left in a shaded area can serve as a breeding ground for mosquitoes,” she said.

She urged people to dispose of tin cans, ceramic pots and other unnecessary containers that have accumulated on their property.

People should also turn over wheelbarrows, plastic wading pools or buckets that could collect water, and should clean out clogged roof gutters every year.

Owners of ornamental pools are urged to aerate them or stock them with fish. Water gardens can become major mosquito producers if they are allowed to stagnate.

She said people should also clean and chlorinate swimming pools they are not using and should be aware that mosquitoes may even breed in the water that collects on pool covers.